Hi @EnterpriseArchitect,
Microsoft says the following about changing the Azure AD Connect service account.
Changes to the service account
Azure AD Connect sync is running under a service account created by the installation wizard. This service account holds the encryption keys to the database used by sync. It is created with a 127 characters long password and the password is set to not expire.
It is unsupported to change or reset the password of the service account. Doing so destroys the encryption keys and the service is not able to access the database and is not able to start.
Here is the process for changing the ADSycn service account password if you still want to try.
Here is the script for changing the ADFS service account.
https://gallery.technet.microsoft.com/scriptcenter/Active-Directory-ddb67df0